Internet sites could be given government-approved age ratings to prevent children accessing inappropriate material, a cabinet minister has suggested, in a move that is likely to trigger fears over web censorship.

The culture secretary, Andy Burnham, says in an interview today that the government is considering the need for "child safe" websites – registered with cinema-style age warnings – to curb access to offensive or damaging online material.

He plans to approach US president-elect Barack Obama's incoming administration with proposals for tight international rules on English language websites, which may include forcing internet service providers, such as BT, Tiscali, Sky and AOL, to ­provide packages restricting access to websites without an age rating.

"There is content that should just not be available to be viewed. That's my view. Absolutely categorical," Burnham, the MP for Leigh in Greater Manchester, told the Daily Telegraph. "If you look back at the people who created the internet, they talked very deliberately about creating a space that governments couldn't reach. I think we are having to revisit that stuff seriously now."

Other safeguards mooted by Burnham include compelling websites such as YouTube and Facebook to remove offensive material within a specified time after they have been alerted to it, and changing Britain's libel laws to make it cheaper for people to sue publishers if they have been defamed online. Internet providers will be urged to adopt the proposals in the new year, but if that failed to work, Burnham said the proposals might have to be enshrined in law.

Burnham, a father of three, insisted his proposals were not intended as an attack on freedom of speech, but were a necessary counterweight to the proliferation of "unacceptable" material on the internet in a similar mould to the 9pm watershed on television. "It worries me – like anybody with children. Leaving your child for two hours unregulated on the internet is not something you can do. The internet has been empowering and democratising in many ways, but we haven't yet got the stakes in the ground to help people navigate their way safely around what can be a very, very complex and quite dangerous world," he added.

He said the change in administration in the US gave an opportunity to set new standards across the internet industry. "The more we seek international solutions to this stuff – the UK and the US working together – the more an international norm will set an industry norm."

His comments are likely to spark a row with those who are opposed to government interference in online publishing.

Admitting his proposals might be criticised as "heavy-handed", Burnham said: "I think that there is definitely a case for clearer standards online. More ability for parents to understand if their child is on a site, what standards it is operating to. What are the protections that are in place?"